1. Field of the Invention
The invention relates to projection device and more particularly to a rotatable projection device.
2. Description of Related Art
A projector is a display device configured to generate a large size image. The imaging theory of the projector includes converting an illumination beam generated by a light source module into an image beam through a light valve, and then projecting the image beam onto a screen or a wall through a lens to generate an image. With the advancement of projection technology and the reduction of fabrication cost, the use of projector has gradually expanded from commercial use to family use.
When the user wants to change the projection direction of the projector, the user needs to move the projector and may therefore result in collision or impact of the projector. Some of the projectors are constituted by two machine bodies that rotate relative to each other. The user rotates one of the machine bodies having a projection lens to alter the projection direction. Nevertheless, when the user rotates the machine bodies relative to each other, the projection of the projector has to be paused and the use thereof is not as convenient.
Taiwan Patent No. M290962 discloses a structure of an advanced hanger for installing a projector on the ceiling. The hanger allows the projector to rotate 360°; however, the operation of angle rotation is not convenient to the user. US Pub. Patent No. 20070146651 discloses a projector having a rotatable lens. However, the rotation device is built-in in the projector and the projector has to undergo maintenance once the rotation device is defective. US Pub. Patent No. 20100039627 discloses a suspended projection device. A projector thereof is pivoted to a suspension arm for rotation. Nevertheless, the suspension aim occupies a lot of space when extended and does not satisfy the trend of miniaturization in projection devices.